# Copyright (c) 2009-2014 Upi Tamminen <desaster@gmail.com>
# See the COPYRIGHT file for more information

import os
import copy
import time
import uuid

from zope.interface import implementer

import twisted
from twisted.cred import portal
from twisted.conch import avatar, interfaces as conchinterfaces
from twisted.conch.ssh import factory, userauth, connection, keys, session, transport, filetransfer, forwarding
from twisted.conch.ssh.filetransfer import FXF_READ, FXF_WRITE, FXF_APPEND, FXF_CREAT, FXF_TRUNC, FXF_EXCL
import twisted.conch.ls
from twisted.python import log, components
from twisted.conch.openssh_compat import primes
from twisted.conch.ssh.common import NS, getNS

import ConfigParser

from kippo.core import ttylog, utils, fs
from kippo.core.config import config
import kippo.core.auth
import kippo.core.honeypot
import kippo.core.ssh
import kippo.core.protocol
from kippo import core

class HoneyPotSSHUserAuthServer(userauth.SSHUserAuthServer):
    def serviceStarted(self):
        userauth.SSHUserAuthServer.serviceStarted(self)
        self.bannerSent = False

    def sendBanner(self):
        if self.bannerSent:
            return
        cfg = config()
        if not cfg.has_option('honeypot', 'banner_file'):
            return
        try:
            data = file(cfg.get('honeypot', 'banner_file')).read()
        except IOError:
            log.msg( 'Banner file %s does not exist!' % \
                cfg.get('honeypot', 'banner_file') )
            return
        if not data or not len(data.strip()):
            return
        data = '\r\n'.join(data.splitlines() + [''])
        self.transport.sendPacket(
            userauth.MSG_USERAUTH_BANNER, NS(data) + NS('en'))
        self.bannerSent = True

    def ssh_USERAUTH_REQUEST(self, packet):
        self.sendBanner()
        return userauth.SSHUserAuthServer.ssh_USERAUTH_REQUEST(self, packet)

# As implemented by Kojoney
class HoneyPotSSHFactory(factory.SSHFactory):
    services = {
        'ssh-userauth': HoneyPotSSHUserAuthServer,
        'ssh-connection': connection.SSHConnection,
        }

    # Special delivery to the loggers to avoid scope problems
    def logDispatch(self, sessionid, msg):
        for dblog in self.dbloggers:
            dblog.logDispatch(sessionid, msg)

    def __init__(self):
        cfg = config()

        # protocol^Wwhatever instances are kept here for the interact feature
        self.sessions = {}

        # for use by the uptime command
        self.starttime = time.time()

        # load db loggers
        self.dbloggers = []
        for x in cfg.sections():
            if not x.startswith('database_'):
                continue
            engine = x.split('_')[1]
            dbengine = 'database_' + engine
            lcfg = ConfigParser.ConfigParser()
            lcfg.add_section(dbengine)
            for i in cfg.options(x):
                lcfg.set(dbengine, i, cfg.get(x, i))
            lcfg.add_section('honeypot')
            for i in cfg.options('honeypot'):
                lcfg.set('honeypot', i, cfg.get('honeypot', i))
            log.msg( 'Loading dblog engine: %s' % (engine,) )
            dblogger = __import__(
                'kippo.dblog.%s' % (engine,),
                globals(), locals(), ['dblog']).DBLogger(lcfg)
            log.startLoggingWithObserver(dblogger.emit, setStdout=False)
            self.dbloggers.append(dblogger)

    def buildProtocol(self, addr):

        _moduli = '/etc/ssh/moduli'
        cfg = config()

        # FIXME: try to mimic something real 100%
        t = HoneyPotTransport()

        if cfg.has_option('honeypot', 'ssh_version_string'):
            t.ourVersionString = cfg.get('honeypot','ssh_version_string')
        else:
            t.ourVersionString = "SSH-2.0-OpenSSH_5.1p1 Debian-5"

        t.supportedPublicKeys = self.privateKeys.keys()

        if ( os.path.exists( _moduli ) ):
            self.primes = primes.parseModuliFile( _moduli )
        if not self.primes:
            ske = t.supportedKeyExchanges[:]
            ske.remove('diffie-hellman-group-exchange-sha1')
            t.supportedKeyExchanges = ske

        # reorder supported ciphers to resemble current openssh more
        t.supportedCiphers = ['aes128-ctr', 'aes192-ctr', 'aes256-ctr', 'aes128-cbc', '3des-cbc', 'blowfish-cbc', 'cast128-cbc', 'aes192-cbc', 'aes256-cbc' ]
        t.supportedPublicKeys = ['ssh-rsa', 'ssh-dss']
        t.supportedMACs = [ 'hmac-md5', 'hmac-sha1']

        t.factory = self
        return t

@implementer(portal.IRealm)
class HoneyPotRealm:

    def __init__(self):
        # I don't know if i'm supposed to keep static stuff here
        self.env = core.honeypot.HoneyPotEnvironment()

    def requestAvatar(self, avatarId, mind, *interfaces):
        if conchinterfaces.IConchUser in interfaces:
            return interfaces[0], \
                HoneyPotAvatar(avatarId, self.env), lambda: None
        else:
            raise Exception, "No supported interfaces found."

class HoneyPotTransport(transport.SSHServerTransport):
    """
    @ivar logintime: time of login

    @ivar interactors: interactors

    @ivar ttylog_open: whether log is open

    @ivar transportId: UUID of this transport

    @ivar _hadVersion: used so we only send key exchange after receive version info
    """

    _hadVersion = False
    ttylog_open = False
    interactors = []
    transportId = ''

    def connectionMade(self):
        self.logintime = time.time()
        self.transportId = uuid.uuid4().hex[:8]

        log.msg( 'New connection: %s:%s (%s:%s) [session: %d]' % \
            (self.transport.getPeer().host, self.transport.getPeer().port,
            self.transport.getHost().host, self.transport.getHost().port,
            self.transport.sessionno) )

        transport.SSHServerTransport.connectionMade(self)

    def sendKexInit(self):
        # Don't send key exchange prematurely
        if not self.gotVersion:
            return
        transport.SSHServerTransport.sendKexInit(self)

    def dataReceived(self, data):
        transport.SSHServerTransport.dataReceived(self, data)
        # later versions seem to call sendKexInit again on their own
        if twisted.version.major < 11 and \
                not self._hadVersion and self.gotVersion:
            self.sendKexInit()
            self._hadVersion = True

    def ssh_KEXINIT(self, packet):
        log.msg( 'Remote SSH version: %s' % self.otherVersionString,)
        return transport.SSHServerTransport.ssh_KEXINIT(self, packet)

    def lastlogExit(self):
        starttime = time.strftime('%a %b %d %H:%M',
            time.localtime(self.logintime))
        endtime = time.strftime('%H:%M',
            time.localtime(time.time()))
        duration = utils.durationHuman(time.time() - self.logintime)
        clientIP = self.transport.getPeer().host
        utils.addToLastlog('root\tpts/0\t%s\t%s - %s (%s)' % \
            (clientIP, starttime, endtime, duration))

    # this seems to be the only reliable place of catching lost connection
    def connectionLost(self, reason):
        for i in self.interactors:
            i.sessionClosed()
        if self.transport.sessionno in self.factory.sessions:
            del self.factory.sessions[self.transport.sessionno]
        self.lastlogExit()
        if self.ttylog_open:
            ttylog.ttylog_close(self.ttylog_file, time.time())
            self.ttylog_open = False
        transport.SSHServerTransport.connectionLost(self, reason)

    def sendDisconnect(self, reason, desc):
        """
        Workaround for the "bad packet length" error message.

        @param reason: the reason for the disconnect.  Should be one of the
                       DISCONNECT_* values.
        @type reason: C{int}
        @param desc: a descrption of the reason for the disconnection.
        @type desc: C{str}
        """
        if not 'bad packet length' in desc:
            # With python >= 3 we can use super?
            transport.SSHServerTransport.sendDisconnect(self, reason, desc)
        else:
            self.transport.write('Protocol mismatch.\n')
            log.msg('Disconnecting with error, code %s\nreason: %s' % \
                (reason, desc))
            self.transport.loseConnection()

class HoneyPotSSHSession(session.SSHSession):

    def __init__(self, *args, **kw):
        session.SSHSession.__init__(self, *args, **kw)
        self.__dict__['request_auth_agent_req@openssh.com'] = self.request_agent

    def request_env(self, data):
	name, rest = getNS(data)
	value, rest = getNS(rest)
	if rest:
	    raise ValueError("Bad data given in env request")
	log.msg('request_env: %s=%s' % (name, value) )
	return 0

    def request_agent(self, data):
	log.msg('request_agent: %s' % repr(data) )
	return 0

    def request_x11_req(self, data):
	log.msg('request_x11: %s' % repr(data) )
	return 0

# FIXME: recent twisted conch avatar.py uses IConchuser here
@implementer(conchinterfaces.ISession)
class HoneyPotAvatar(avatar.ConchUser):

    def __init__(self, username, env):
        avatar.ConchUser.__init__(self)
        self.username = username
        self.env = env
        self.fs = fs.HoneyPotFilesystem(copy.deepcopy(self.env.fs))
        self.hostname = self.env.cfg.get('honeypot', 'hostname')

        self.channelLookup.update({'session': HoneyPotSSHSession})
        self.channelLookup['direct-tcpip'] = KippoOpenConnectForwardingClient

        # sftp support enabled only when option is explicitly set
        if self.env.cfg.has_option('honeypot', 'sftp_enabled'):
            if ( self.env.cfg.get('honeypot', 'sftp_enabled') == "true" ):
                self.subsystemLookup['sftp'] = filetransfer.FileTransferServer

        self.uid = self.gid = core.auth.UserDB().getUID(self.username)
        if not self.uid:
            self.home = '/root'
        else:
            self.home = '/home/' + username

    def openShell(self, protocol):
        serverProtocol = core.protocol.LoggingServerProtocol(
            core.protocol.HoneyPotInteractiveProtocol, self, self.env)
        serverProtocol.makeConnection(protocol)
        protocol.makeConnection(session.wrapProtocol(serverProtocol))

    def getPty(self, terminal, windowSize, attrs):
        log.msg( 'Terminal size: %s %s' % windowSize[0:2] )
        self.windowSize = windowSize
        return None

    def execCommand(self, protocol, cmd):
        cfg = config()
        if not cfg.has_option('honeypot', 'exec_enabled') or \
                cfg.get('honeypot', 'exec_enabled').lower() not in \
                    ('yes', 'true', 'on'):
            log.msg( 'Exec disabled. Not executing command: "%s"' % cmd )
            raise core.exceptions.NotEnabledException, \
                'exec_enabled not enabled in configuration file!'
            return

        log.msg( 'exec command: "%s"' % cmd )
        serverProtocol = kippo.core.protocol.LoggingServerProtocol(
            kippo.core.protocol.HoneyPotExecProtocol, self, self.env, cmd)
        serverProtocol.makeConnection(protocol)
        protocol.makeConnection(session.wrapProtocol(serverProtocol))

    def closed(self):
        pass

    def eofReceived(self):
        pass

    def windowChanged(self, windowSize):
        self.windowSize = windowSize

def getRSAKeys():
    cfg = config()
    public_key = cfg.get('honeypot', 'rsa_public_key')
    private_key = cfg.get('honeypot', 'rsa_private_key')
    if not (os.path.exists(public_key) and os.path.exists(private_key)):
        log.msg( "Generating new RSA keypair..." )
        from Crypto.PublicKey import RSA
        from twisted.python import randbytes
        KEY_LENGTH = 2048
        rsaKey = RSA.generate(KEY_LENGTH, randbytes.secureRandom)
        publicKeyString = keys.Key(rsaKey).public().toString('openssh')
        privateKeyString = keys.Key(rsaKey).toString('openssh')
        with file(public_key, 'w+b') as f:
            f.write(publicKeyString)
        with file(private_key, 'w+b') as f:
            f.write(privateKeyString)
    else:
        with file(public_key) as f:
            publicKeyString = f.read()
        with file(private_key) as f:
            privateKeyString = f.read()
    return publicKeyString, privateKeyString

def getDSAKeys():
    cfg = config()
    public_key = cfg.get('honeypot', 'dsa_public_key')
    private_key = cfg.get('honeypot', 'dsa_private_key')
    if not (os.path.exists(public_key) and os.path.exists(private_key)):
        log.msg( "Generating new DSA keypair..." )
        from Crypto.PublicKey import DSA
        from twisted.python import randbytes
        KEY_LENGTH = 1024
        dsaKey = DSA.generate(KEY_LENGTH, randbytes.secureRandom)
        publicKeyString = keys.Key(dsaKey).public().toString('openssh')
        privateKeyString = keys.Key(dsaKey).toString('openssh')
        with file(public_key, 'w+b') as f:
            f.write(publicKeyString)
        with file(private_key, 'w+b') as f:
            f.write(privateKeyString)
    else:
        with file(public_key) as f:
            publicKeyString = f.read()
        with file(private_key) as f:
            privateKeyString = f.read()
    return publicKeyString, privateKeyString

@implementer(conchinterfaces.ISFTPFile)
class KippoSFTPFile:

    def __init__(self, server, filename, flags, attrs):
        self.server = server
        self.filename = filename
        self.transfer_completed = 0
        self.bytes_written = 0
        openFlags = 0
        if flags & FXF_READ == FXF_READ and flags & FXF_WRITE == 0:
            openFlags = os.O_RDONLY
        if flags & FXF_WRITE == FXF_WRITE and flags & FXF_READ == 0:
            openFlags = os.O_WRONLY
        if flags & FXF_WRITE == FXF_WRITE and flags & FXF_READ == FXF_READ:
            openFlags = os.O_RDWR
        if flags & FXF_APPEND == FXF_APPEND:
            openFlags |= os.O_APPEND
        if flags & FXF_CREAT == FXF_CREAT:
            openFlags |= os.O_CREAT
        if flags & FXF_TRUNC == FXF_TRUNC:
            openFlags |= os.O_TRUNC
        if flags & FXF_EXCL == FXF_EXCL:
            openFlags |= os.O_EXCL
        if attrs.has_key("permissions"):
            mode = attrs["permissions"]
            del attrs["permissions"]
        else:
            mode = 0777
        fd = server.fs.open(filename, openFlags, mode)
        if attrs:
            self.server.setAttrs(filename, attrs)
        self.fd = fd

        # cache a copy of file in memory to read from in readChunk
        if flags & FXF_READ == FXF_READ:
            self.contents = self.server.fs.file_contents(self.filename)

    def close(self):
        if ( self.bytes_written > 0 ):
            self.server.fs.update_size(self.filename, self.bytes_written)
        return self.server.fs.close(self.fd)

    def readChunk(self, offset, length):
        return self.contents[offset:offset+length]

    def writeChunk(self, offset, data):
        self.server.fs.lseek(self.fd, offset, os.SEEK_SET)
        self.server.fs.write(self.fd, data)
        self.bytes_written += len(data)

    def getAttrs(self):
        s = self.server.fs.fstat(self.fd)
        return self.server._getAttrs(s)

    def setAttrs(self, attrs):
        raise NotImplementedError

class KippoSFTPDirectory:

    def __init__(self, server, directory):
        self.server = server
        self.files = server.fs.listdir(directory)
        self.dir = directory

    def __iter__(self):
        return self

    def next(self):
        try:
            f = self.files.pop(0)
        except IndexError:
            raise StopIteration
        else:
            s = self.server.fs.lstat(os.path.join(self.dir, f))
            longname = twisted.conch.ls.lsLine(f, s)
            attrs = self.server._getAttrs(s)
            return (f, longname, attrs)

    def close(self):
        self.files = []

@implementer(conchinterfaces.ISFTPServer)
class KippoSFTPServer:

    def __init__(self, avatar):
        self.avatar = avatar
        self.fs = self.avatar.fs

    def _absPath(self, path):
        home = self.avatar.home
        return os.path.abspath(os.path.join(home, path))

    def _setAttrs(self, path, attrs):
        if attrs.has_key("uid") and attrs.has_key("gid"):
            self.fs.chown(path, attrs["uid"], attrs["gid"])
        if attrs.has_key("permissions"):
            self.fs.chmod(path, attrs["permissions"])
        if attrs.has_key("atime") and attrs.has_key("mtime"):
            self.fs.utime(path, attrs["atime"], attrs["mtime"])

    def _getAttrs(self, s):
        return {
            "size" : s.st_size,
            "uid" : s.st_uid,
            "gid" : s.st_gid,
            "permissions" : s.st_mode,
            "atime" : int(s.st_atime),
            "mtime" : int(s.st_mtime)
        }

    def gotVersion(self, otherVersion, extData):
        return {}

    def openFile(self, filename, flags, attrs):
        log.msg( "SFTP openFile: %s" % filename )
        return KippoSFTPFile(self, self._absPath(filename), flags, attrs)

    def removeFile(self, filename):
        log.msg( "SFTP removeFile: %s" % filename )
        return self.fs.remove(self._absPath(filename))

    def renameFile(self, oldpath, newpath):
        log.msg( "SFTP renameFile: %s %s" % (oldpath, newpath) )
        return self.fs.rename(self._absPath(oldpath), self._absPath(newpath))

    def makeDirectory(self, path, attrs):
        log.msg( "SFTP makeDirectory: %s" % path )
        path = self._absPath(path)
        self.fs.mkdir2(path)
        self._setAttrs(path, attrs)
        return

    def removeDirectory(self, path):
        log.msg( "SFTP removeDirectory: %s" % path )
        return self.fs.rmdir(self._absPath(path))

    def openDirectory(self, path):
        log.msg( "SFTP OpenDirectory: %s" % path )
        return KippoSFTPDirectory(self, self._absPath(path))

    def getAttrs(self, path, followLinks):
        log.msg( "SFTP getAttrs: %s" % path )
        path = self._absPath(path)
        if followLinks:
            s = self.fs.stat(path)
        else:
            s = self.fs.lstat(path)
        return self._getAttrs(s)

    def setAttrs(self, path, attrs):
        log.msg( "SFTP setAttrs: %s" % path )
        path = self._absPath(path)
        return self._setAttrs(path, attrs)

    def readLink(self, path):
        log.msg( "SFTP readLink: %s" % path )
        path = self._absPath(path)
        return self.fs.readlink(path)

    def makeLink(self, linkPath, targetPath):
        log.msg( "SFTP makeLink: %s" % path )
        linkPath = self._absPath(linkPath)
        targetPath = self._absPath(targetPath)
        return self.fs.symlink(targetPath, linkPath)

    def realPath(self, path):
        log.msg( "SFTP realPath: %s" % path )
        return self.fs.realpath(self._absPath(path))

    def extendedRequest(self, extName, extData):
        raise NotImplementedError

components.registerAdapter( KippoSFTPServer, HoneyPotAvatar, conchinterfaces.ISFTPServer)

def KippoOpenConnectForwardingClient(remoteWindow, remoteMaxPacket, data, avatar):
    remoteHP, origHP = twisted.conch.ssh.forwarding.unpackOpen_direct_tcpip(data)
    log.msg( "direct-tcp connection attempt to %s:%i" % remoteHP )
    return None

# vim: set et sw=4 et: